Maneuvering command display for aircraft

ABSTRACT

Maneuvering commands are displayed to an aircraft pilot by three conspicuous bars on a background panel that has horizontal and vertical axes of symmetry. The bars swing about their ends nearest the intersection of said axes. Two bars, extending symmetrically to opposite sides of the vertical axis signify pitch maneuvers, being aligned with the horizontal axis when pitch is satisfactory or inclined to it in the direction of required pitch change. The third bar is aligned with the vertical axis when heading is satisfactory or inclined to it in the direction of required heading change.

United States Patent Nordstriirn [$4] MANEUVERING COMMAND DISPLAY FOR AIRCRAFT [72] Inventor: Knut Lennart Nordstrom, Saab- Scania Aktiebolag S-58l-88, Linkoping, Sweden [22] Filed: May5,1971

2] Appl. No.: 140,340

I 301 Foreign Applications Priority Data May ll, I970 Sweden ..6389/70 [52] US. Cl. ..340/27 AT, 33/204 C [51] Int. Cl. ..G05d 1/08, B64d 43/00 [58] Field of Search .....340/27 R, 27 AT, 27 NA, 26,

[56] References Cited UNITED STATES PATENTS Kellogg ..3 40/26 [451 Sept. 12, 1971 Primary Examiner-Kathleen H. Clafiy Assistant ExaminerTh0mas L. Kundert Attorney-Ira Milton Jones [57] ABSTRACT Maneuvering commands are displayed to an aircraft pilot by three conspicuous bars on a background panel that has horizontal and vertical axes of symmetry. The bars swing about their ends nearest the intersection of said axes. Two bars, extending symmetrically to opposite sides of the vertical axis signify pitch maneuvers, being aligned with the horizontal axis when pitch is satisfactory or inclined to it in the direction of required pitch change. The third bar is aligned with the vertical axis when heading; is satisfactory or inclined to it in the direction of required heading change.

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ATTORNEY MANEUVERING COMMAND DISPLAY FOR AIRCRAFT This invention relates to apparatus for displaying maneuvering commands to the pilot of an aircraft, and is concerned more specifically with maneuvering command display means that can be readily perceived and interpreted with the use of only peripheral vision.

There are certain maneuvering situations in which the pilot of an aircraft is required to shift his attention and vision rapidly from instrument to instrument, and often, also, to include in his scan the environment outside the aircraft. Pilots who engage in instrument flight are aware of the fatigue that results from shifting the eyes from one instrument to another, and focusing upon and reading each instrument in turn. For the pilot to shift his eyes between the instrument panel and the exterior of the aircraft involves additional elements that induce fatigue, since this requires major adjustments of the several eye muscles that control convergence, focus and light adaptation; and while these adjustments are performed almost automatically, their repetition at the necessarily high frequency involved in some flight situations is very fatiguing.

With these considerations in mind, it is the general object of this invention to provide an aircraft instrument by which maneuvering command signals can be displayed to the pilot, and which canbe readily seen with the use of only peripheral vision, so the! its signals can be perceived and interpreted even while the pilots central or foveal field of vision is fixed outside the aircraft and focused at a distance or is concentrated on other instruments that require closer examination.

A known type of maneuvering command display device that is intended to be perceived with peripheral vision comprises rotatably mounted, elongated cylinders each having a helical pattern around its cylindrical surface. There is a cylinder for each of the maneuvering axes, and each cylinder is caused to rotate in a direction that indicates the direction of a required maneuver about its corresponding axis and at a rate that indicates the magnitude of the commanded maneuver. In a modified form of this known display, two cylinders have counter-directed helical patterns, and one is mounted concentrically within the other and is visible therethrough. Upon rotation of the respective cylinders to signify a required maneuver, their helical patterns cooperate to define a square pattern which appears to move up, down, right or left, or in vector directions therebetween, to signify the direction of maneuver required.

With both of these prior types of display devices a command for a change of direction is signified by movement of a pattern symbol, and a satisfactory state of motion is denoted by the pattern remaining stationary. Both of these display devices have the disadvantage that their displays are not readily perceptible to peripheral vision when the display pattern is stationery, and also when the movement of the pattern is small.

Hence it is another object of this invention to provide a device for displaying maneuvering commands wherein the display is one that can be readily perceived and interpreted with the use of peripheral vision alone, by reason of the fact that the display symbols define a bold, simple pattern that varies in accordance with the type of maneuver commanded, so that observation and interpretation of the display is aided not only by the pattern and placement of the symbol elements but also by their movement away from and back to a defined and readily recognized neutral position as they signify the satisfaction of maneuvering requirements.

It is also an object of this invention to provide a maneuvering command display wherein the displayed maneuver command symbols cooperate to define extremely simple patterns that are readily perceptible to peripheral vision and have almost self-evident significance, and wherein the displacement of a symbol element from a predetermined neutral position by its direction and magnitude respectively denotes the sense and magnitude of a required maneuver denoted by the symbol element.

A further object of this invention is to provide maneuver command display means of the character described whereby commands can be given for composite maneuvers, such as simultaneous change of vertical and lateral direction, by means of a pattern of command symbols that is simple enough to be readily perceptible with peripheral vision.

It is also an object of this invention to provide a display which can be perceived with only peripheral vision and which can present maneuvering commands by which the aircraft can be brought to a predetermined situation that is completely defined both is space and in time.

With these observations and objectives in mind, the manner in which the invention achieves its purpose will be appreciated from the following description and the accompanying drawings, which exemplify the invention, it being understood that changes may be made in the specific apparatus disclosed herein without departing from the essentials of the invention set forth in the appended claims.

The accompanying drawings illustrate several complete examples of embodiments of the invention constructed according to the best modes so far devised for the practical application of the principles thereof, and in which:

FIG. 1 is a perspective view of a mechanically operating maneuvering command display device mounted in the cockpit of an airplane, as seen by the pilot of the airplane;

FIG. 2 is a view generally similar to FIG. I but illustrating a modifiedembodiment of the invention comprising an electronically operated maneuvering command display device wherein maneuvering command signals are displayed on a transparent screen in the pilots normal forward field of vision;

FIGS. 3a-3e illustrate various maneuver command display patterns obtainable with the device illustrated in FIG. 1;

FIGS. 4a-4e are views similar to FIGS. 3a-3e, respectively, but showing the corresponding displays on a modified embodiment of the device;

FIGS. 5a-5e are likewise views similar to FIGS. 3a-3e, respectively, but showing the displays as they would appear on the embodiment of the device illustrated in FIG. 2;

FIG. 6 is a schematic block diagram of the units in a maneuver command signal system comprising a display device like that illustrated in FIG. 1;

FIG. 7, is a view generally similar to FIG. 6 but illustrating a display device like that of FIG. 2 together with its associated equipment;

FIG. 8 is an enlarged front view of the command signal display device shown in FIG. 1;

FIG. 9 is a perspective view of the display device shown in FIG. 8, illustrating more or less diagrammatically the drive means and motion transmitting means by which its display symbols are actuated; and

FIGS. 10 and 11 illustrate displays of maneuver command and flight situation information on a form of the device shown in FIG. 2.

Referring now more particularly to the accompanying drawings, the numeral designates generally an aircraft instrument panel above which there is a windshield 6 through which the pilot can look forwardly out of the aircraft. The maneuvering command display device of this invention, which is designated generally by 7, is mounted in such a location as to be in or closely adjacent to the pilots normal forward line of vision, so that the display that the device provides is within the pilots peripheral vision both when he is looking forwardly through the windshield and when he is looking at instruments on the panel.

The mechanically actuated display device of the embodiment of the invention illustrated in FIG. 1 is mounted at the top center of the instrument panel. The electronic embodiment of the display device illustrated in FIG. 2 comprises a transparent projection screen 12' that projects up from the center of the instrument panel so as to be in the pilots range of vision through the windshield.

To further facilitate observation of the display with peripheral vision, the primary flight instruments most frequently referred to, and which are designated by 8, are preferably arranged adjacent to the face of the display device 7. As illustrated, a radar screen or attitude indicator is mounted in the location 9 just below the display device.

As indicated in FIGS. 6 and 7, the display device is connected with the output of a computer that receives inputs from various flight and navigation devices 11, such as gyros for measuring the attitude angles of the aircraft, airspeed, altitude and angle of attack sensors, radio navigation systems, instrument landing systems and the like. The inputs to the computer thus correspond in part to a predetermined situation to which the aircraft is to be maneuvered, and in part to the currently existing situation of the aircraft, and the output of the computer that is fed to the display device comprises signals that correspond to the computed maneuvering of the aircraft required to bring it from its existing situation to the predetermined situation.

In general, the computer output signals are translated by the display device into a display pattern of bars that signify to the pilot by their arrangement and movement the maneuvers that he must accomplish to bring the aircraft to the predetermined situation and to maintain it there.

Considering first the mechanical embodiment of the invention, the pilot sees before him a screen or background 12 having a shape in outline that is symmetrical to a vertical axis 14 and preferably also to a horizontal axis 15, and on which moveable bars 16 and 17 are superimposed. Preferably the screen is black and the bars are white, for maximum contrast and to facilitate observation with peripheral vision.

Each of the bars 16 and 17 is mounted for pivotal motion about one of its ends, to swing across the face of the screen, and the pivoted ends of the bars are at or near the intersection of the axes l4 and 15. The two bars 16 have their pivot axes on the horizontal axis 15, and they extend symmetrically to opposite sides of the vertical axis 14. The pivot axis of the bar 17 is on the vertical axis, and it extends generally upwardly from the horizontal axis. The positions of the two bars 16 denote pitching (climb-dive) maneuvers, while the positions of the bar 17 denote lateral (left-right) maneuvers.

FIGS. 3a-3e depict various maneuvering commands signified by the bars 16 and 17 in the device illustrated in FIG. 1, wherein the pivot axes of the bars 16 are spaced to opposite sides of the vertical axis, and the generally upright bar 17 has its pivot axis on the intersection of the axes 14 and 15. FIGS. 4a-4e respectively, depict corresponding command signal patterns displayed by a modified form of the FIG. 1 embodiment, wherein all three bars have their pivot axes on the intersection of the axes 14 and 15.

When the display device signifies a satisfactory state of pitch and lateral motion, the bars 16 are aligned with one another on the horizontal axis 15, and the upright bar 17 is aligned with the vertical axis 14, all as illustrated in FIGS. 3a and 4a, so that the pattern defined by the bars has the form of an inverted T.

To signify a change in pitch direction, the bars 16 swing up or swing down in unison, always remaining symmetrical to the vertical axis 14. The direction in which the bars 16 are inclined to the horizontal axis indicates the direction in which pitching motion is to be changed and the amount of such inclination indicates the magnitude of the required change. Thus FIGS. 3b and 4b illustrate a command for an upward movement (e.g., from level flight to climb, or from dive toward level flight), while FIGS. 3c and 4c illustrate displays that command a downward movement (e.g., from level flight to dive or from climb toward level flight). As in FIGS. 3a and 4a, the position of the bar 17 in FIGS. 3b, 3c, 4b and 4c, aligned with the vertical axis, denotes that the heading is satisfactory, that is, that no lateral change in flight direction is to be made.

This displays illustrated in FIGS. 3d and 4d signify that pitching motion is satisfactory but that a turn to the left is to be made. FIGS. 3e and 4e illustrate patterns which command composite maneuvers, signifying, in each case, that the aircraft is to be given an upward change of pitch direction and is to be turned to the right.

The bold and simple patterns produced by the display device are readily observed with peripheral vision and can be interpreted without the need for closer inspection of the display. Furthermore, the swinging movements of the bars as they assume various patterns draw attention to the need for maneuvering control motions and facilitate perception of the patterns. Since the patterns formed by the bars are well defined, the axes l4 and 15 need not actually be delineated on the panel or screen 12 that the bars overlie. Note that all displays are self-explanatory if the pilot is merely instructed to fly toward the needles.

As shown in FIG. 9, the mechanism by which the bars are actuated comprises a moving coil 19 that is connected with the bars 16 through a known type of wishbone and bell crank linkage 20 by which it actuates them in unison; and a moving coil 21 that is connected through a parallelogram linkage 22 with the bar 17. The moving coils 19 and 21 are of course connected with the computer to receive output signals from it.

As shown in FIGS. 8 and 9, the mechanical maneuvering command display apparatus can be arranged to provide attitude information in addition to command signals, by means of a horizon bar 23. In straight and level flight the horizon bar is on the horizontal axis 15, and, in the manner of the classical artificial horizon, it remains parallel with the actual horizon, tilting relative to the axis as the airplane rolls and moving bodily up and down relative to said axis with changes in the pitch attitude of the aircraft. The tilting axis of the horizon bar 23 is of course at its center and remains on the vertical axis 14 in all positions of its vertical displacement.

Tilting motion of the horizon bar is effected by means of a rotor coil 25 which is connected with the center of the bar through a shaft 26 and which can of course be slaved to an attitude gyro (not shown). Vertical motion of the horizon bar is effected by means of another rotor coil 27, suitably linked to the shaft 26 and which can likewise be slaved to the attitude gyro.

Provision can also be made for a display of altitude information, but to avoid unnecessary distraction and to obviate the need for focusing upon the altitude display in order to perceive small variations in it, altitude information is displayed only when the aircraft is less than a predetermined critical distance above the ground.

The altitude display symbol can comprise a pair of vertical bars 29, spaced a short distance to each side of the vertical axis 14 and which move vertically, in unison, during changes in altitude within the critical range. The altitude display bars are actuated by a rotor coil 30 which is connected with them through suitable motion transmission means 31 and which can be slaved to an altitude sensor (not'shown) that can be either an aneroid or (preferably) a radar altimeter. When the altitude of the aircraft exceeds the predetermined critical value (e.g., 500 feet), the altitude display bars will be in an inoperative position. As the airplane descends through and below the critical altitude the altitude bars will signify the prevailing altitude by their vertical position. It will be appreciated that the altitude bars can function according to any desired scheme of movement that is reasonably self-explanatory. For example, they can be concealed at a level beneath the visible part of the background screen 12 when altitude of the aircraft exceeds the critical value, and within the critical range they can signify the altitude of the aircraft by the distance H between their bottoms and the horizontal axis 15. As an aid to interpretation of the altitude display, the bars can be so dimensioned that their size represents some significant unit on the altitude display scale, as for example each bar can have a length that corresponds to 200 ft. on its altitude scale.

In the embodiment of the invention depicted in FIGS. 2 and 7 the bars 16' and 17 comprising the display symbols are delineated by light projected onto the transparent screen 12 and generated electronically. As

in the first described embodiment, various inputs are fed to a computer 10. The output side of the computer is connected with a maneuvering command symbol generator 33, which in turn controls a cathode ray tube 34. The command display symbols appear on the screen of the cathode ray tube, and are projected onto the transparent display screen 12' by means of a mirror 35 and collimating optics 36.

Preferably the bars 16' and 17' are discontinuous, that is, each has the appearance of a line of dashes 38. The maneuvering command display patterns will then appear as shown in FIGS. 5a-5e, which respectively denote the same maneuver commands as FIGS. 3a-3e and 4a-4e.

In this case speed commands can be incorporated in the maneuvering command display pattern by providing for movement of the clashes that comprise the direction command bars 16' and 17'. Thus, to denote a command to increase speed, the dashes defining the bars can be caused to move along them in directions towards their pivot ends (i.e., convergently along the several bars), thereby creating an impression that the pattern is moving forward, and giving the pilot the feeling that he is falling behind the pattern so that his more or less automatic response will be to increase his velocity. Conversely, when the velocity is excessive, the dashes that define the several bars are caused to move in the direction away from the pivoted ends of the bars, creating the impression that the pattern is expanding or coming nearer. When forward velocity is correct for the predetermined situation, the dashes will of course remain stationary along the bars that they define, giving the pilot the feeling that he is maintaining a desired fixed distance from the pattern. The magnitude of a required speed change can be denoted by the rate of movement of the dashes along the bars.

It will be observed that with the display presenting both directional and velocity commands as just described, all commands necessary to bring the aircraft to a flight situation that is predetermined as to both space and time can be presented in the form of a simple unitary pattern that can be perceived with the use of peripheral vision and comprehended almost automatically.

FIGS. 10 and 11 illustrate supplemental modifications that can be made to the embodiment of the invention illustrated in FIGS. 2 and 7, whereby quantitative information concerning the prevailing flight situation can be displayed as a supplement to the maneuvering command display.

FIG. 10 illustrates a supplemental situation display for the navigation phase of a flight. The horizontal axis 15 of the display is fixed in relation to the wings of the aircraft, as is the vertical axis 14. However, a heading scale 39 is generated and displayed above the heading command bar 17', along a line which remains parallel to the horizon, and the heading along that scale is designated by a pointer 41 that remains on a line normal to the horizontal scale and through the intersection of the axes 14 and 15. An altitude scale 42 is displayed to the right of the maneuvering command symbol, along a line which remains in true vertical. The prevailing altitude is designated by a pointer 43 adjacent to the altitude scale, on a true horizontal line through the intersection of the reference axes 14 and 15. To the left of the heading scale 39 and to the right of the altitude scale are displayed lines 44 denoting principal values along a flight path angle scale. The flight path angle is read by reference to the point 45 at which the reference axes l4 and intersect, which point is identifiable not only by reference to the bars 16' and 17' but also by reason of the fact that it is defined by perpendiculars to the heading scale and altitude scale lines through the pointers 41 and 43. The flight path angle value lines 44 remain truly horizontal.

FIG. 1 1 illustrates a flight situation display mode that is particularly suitable for the landing approach phase of a flight. In this case the reference axes l4 and 15 are fixed with respect to the ground, so that the horizontal axis 15 remains in true horizontal. The true horizon is indicated on the display by a generated line 47 that coincides with the actual horizon 48 as seen in the pilots field of view, as illustrated in FIG. 2. The heading scale 39 is in this case delineated along the generated horizon line 47. The generated horizon line also serves as an index cooperating with an altitude scale 42 to the right of the command display, to provide an indication of altitude. in this case the flight path angle scale is omitted.

From the foregoing description taken with the accompanying drawings it will be apparent that this invention provides a display by which maneuvering commands are so presented to the pilot of an aircraft that he can readily perceive them with only peripheral visibn, are denoted by maneuvering command symbols which are so simple as to be almost self-explanatory, so that the pilot can follow them almost automatically, and can be accompanied by a simple display of the existing flight situation.

Those skilled in the art will appreciate that the invention can be embodied in forms other than as herein disclosed for purposes of illustration.

The invention is defined by the following claims:

1. Means connectable with the output of a computing device for providing a display of maneuver commands to a pilot of an aircraft, which display is discernable with peripheral vision and signifies the maneuvering required to bring the aircraft from its existing situation to a predetermined situation, said means comprising:

A. means defining a display field having a vertical axis of symmetry and a horizontal axis;

B. means delineating a pair of straight bars, each having an end on said horizontal axis and adjacent to said vertical axis, said bars being swingable in unison about their said ends between a position in which the bars are aligned with one another along the horizontal axis to signify satisfactory vertical movement and positions in which the bars are symmetrically oblique to the horizontal axis to signify required changes in vertical movement in the direction in which the bars are inclined and of a magnitude corresponding to the amount of their inclination; and

C. means defining a third straight bar having one of its ends on said vertical axis and adjacent to the horizontal axis, said third bar being swingable about its said end between a position aligned with the vertical axis, signifying a satisfactory heading,

terized by:

D. said display field means comprising a panel having I a dark substantially flat surface; and

E. the means defining each of said bars comprising a rigid element of light color mounted in front of said surface to swing thereacross.

3. The display means of claim 1, further characterized by:

D. said display field means comprising a transparent projection screen; and

E. the means defining each of said bars comprising means for generating and projecting onto said screen a row of luminous dashes.

4. The display means of claim 3, further characterized by:

F. means for causing the dashes of the rows that define said bars to move lengthwise therealong in a direction corresponding to the sign of a required change in forward velocity and at a rate corresponding to the magnitude of such required change.

5. A display device by which maneuvering commands are displayed to a pilot of an aircraft, in following which he brings the aircraft to a predetermined situation, and which display device is of the type having a defined display screen, means defining generally upright bar-like indicator means having one end that remains on a vertical axis of symmetry on said screen and which swings about its said end to denote required changes in heading by its inclination to said vertical axis of symmetry, and other bar-like indicator means swingable up and down to denote required changes in vertical flight path, said display device being characterized by:

A. said upright bar-like indicator means having its said one end substantially at a midpoint on the screen and extending generally upwardly therefrom;

B. said other bar-like indicator means comprising a pair of generally horizontal bar-like indicator elements,

1. each having one end that remains on a horizontal line adjacent to said one end of the upright bar-like indicator,

2. said ends of the bar-like indicator elements being nearer one another and equidistant from said vertical axis of symmetry, and

3. said bar-like indicator elements being swingable in unison about their said ends, symmetrically to said vertical axis of symmetry, between a position of horizontal alignment signifying no required change in vertical flight path and positions in which they are inclined to said horizontal line and signify a required change in vertical flight path in the direction of their inclination.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent NO- 3 691 520 Dated September 12 1972 Inventor(s) 4 Knut Lennart Nordstrom It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On the frontispiece of the patent:

The date of issue should read September 12, 1972-- En'gnzd and Scaled this twelfth Day Of July 1977 [SEAL] Arrest:

RUTH c. MASON c. MARSHALL DANN Allesling ff Commissioner of Patents and Trademarks 

1. Means connectable with the output of a computing device for providing a display of maneuver commands to a pilot of an aircraft, which display is discernable with peripheral vision and signifies the maneuvering required to bring the aircraft from its existing situation to a predetermined situation, said means comprising: A. means defining a display field having a vertical axis of symmetry and a horizontal axis; B. means delineating a pair of straight bars, each having an end on said horizontal axis and adjacent to said vertical axis, said bars being swingable in unison about their said ends between a position in which the bars are aLigned with one another along the horizontal axis to signify satisfactory vertical movement and positions in which the bars are symmetrically oblique to the horizontal axis to signify required changes in vertical movement in the direction in which the bars are inclined and of a magnitude corresponding to the amount of their inclination; and C. means defining a third straight bar having one of its ends on said vertical axis and adjacent to the horizontal axis, said third bar being swingable about its said end between a position aligned with the vertical axis, signifying a satisfactory heading, and positions inclined to the vertical axis and signifying a required change of heading in the direction of inclination and of a magnitude corresponding to the amount of inclination.
 2. The display means of claim 1, further characterized by: D. said display field means comprising a panel having a dark substantially flat surface; and E. the means defining each of said bars comprising a rigid element of light color mounted in front of said surface to swing thereacross.
 2. said ends of the bar-like indicator elements being nearer one another and equidistant from said vertical axis of symmetry, and
 3. said bar-like indicator elements being swingable in unison about their said ends, symmetrically to said vertical axis of symmetry, between a position of horizontal alignment signifying no required change in vertical flight path and positions in which they are inclined to said horizontal line and signify a required change in vertical flight path in the direction of their inclination.
 3. The display means of claim 1, further characterized by: D. said display field means comprising a transparent projection screen; and E. the means defining each of said bars comprising means for generating and projecting onto said screen a row of luminous dashes.
 4. The display means of claim 3, further characterized by: F. means for causing the dashes of the rows that define said bars to move lengthwise therealong in a direction corresponding to the sign of a required change in forward velocity and at a rate corresponding to the magnitude of such required change.
 5. A display device by which maneuvering commands are displayed to a pilot of an aircraft, in following which he brings the aircraft to a predetermined situation, and which display device is of the type having a defined display screen, means defining generally upright bar-like indicator means having one end that remains on a vertical axis of symmetry on said screen and which swings about its said end to denote required changes in heading by its inclination to said vertical axis of symmetry, and other bar-like indicator means swingable up and down to denote required changes in vertical flight path, said display device being characterized by: A. said upright bar-like indicator means having its said one end substantially at a midpoint on the screen and extending generally upwardly therefrom; B. said other bar-like indicator means comprising a pair of generally horizontal bar-like indicator elements, 